Image Pickup Lens, Image Pickup Apparatus, and Mobile Terminal

ABSTRACT

An image pickup lens LN includes four blocks of lens blocks Ci (i= 0  to  4 ). Lens substrate Li 2  is different in material from lens portions Li 1  and Li 3 . First lens block C 1  has positive power, second lens block C 2  has negative power, and fourth lens block C 4  has a concave shape facing an image side in a paraxial region. At least one of lens portions with a concave shape in the paraxial region satisfies the conditional expression νn&lt;40 (where νn is an Abbe number of a lens portion having a concave shape in the paraxial region), and first lens block C 1  satisfies the conditional expression 0.5&lt;f1/f&lt;1.5 (where f1 is a composite focal length of the first lens block and f is a composite focal length of the total system).

TECHNICAL FIELD

The present invention relates to an image pickup lens, an image pickupapparatus and a mobile terminal. More particularly, it relates to animage pickup apparatus for picking up an image of a subject with animage pickup element (for example, a solid-state imaging device such asan image sensor of CCD (Charge Coupled Devices) type and an image sensorof CMOS (Complementary Metal-Oxide Semiconductor) type), a mobileterminal in which the image pickup apparatus is mounted, and an imagepickup lens which includes, for example, a waferscaled lens suitable formass production, for forming an optical image on a light-receivingsurface of an image pickup element.

BACKGROUND ART

A compact and thin-type image pickup apparatus has come to be mounted ona mobile terminal representing a compact and thin-type electronichardware (such as a cell phone and PDA (Personal Digital Assistant)),whereby, it has become possible to transmit mutually not only voiceinformation but also image information to a remote location. As imagepickup elements used for these image pickup apparatuses, a solid-stateimaging device such as an image sensor of a CCD type and an image sensorof a CMOS type are used.

In recent years, an image pickup element with fine pixel pitch has beenemployed for an image pickup apparatus with a wide angle of view to bemounted on a mobile terminal, for the purpose of downsizing of the imagepickup apparatus. Such the trend continues to be furthermoreaccelerated. However, an image pickup element with a small pixel pitchexhibits a deteriorated SN ratio under a lower brightness condition,which becomes a cause of noise. To solve it, a development of an imagepickup lens having a small F-number, and a high performance ofrepresentation has been required. At the same time, telecentricity hasalso been required for solving an insufficient light-amount of a ray tobe formed into an image on a periphery of the image area. To respond tosuch the requirements, Patent Literatures 1 and 2 propose image pickuplenses in which the F-number is set to be as small as 2.4 to 2.8.Further, Patent Literatures 3 to 7 propose image pickup lenses aimed ata realization of mass production.

CITATION LIST Patent Literature

-   Patent Literature 1: JP-A No. 2007-264180-   Patent Literature 2: JP-A No. 2007-279282-   Patent Literature 3: JP-B No. 3929479-   Patent Literature 4: JP-B No. 3976781-   Patent Literature 5: JP-A No. 2006-323365-   Patent Literature 6: JP-B No. 3946245-   Patent Literature 7: JP-B No. 3976782

SUMMARY OF INVENTION Technical Problem

In order to realize a small F-number and a high performance ofrepresentation, correction of chromatic aberrations and other variousaberrations has been tried by employing a large number of lenses such asfive lenses in image pickup lenses proposed in Patent Literatures 1 and2. However, the total length of them has been increased because of theirconstriction having a large number of lenses. Further, glass has beenused in a part of lenses for trying the enhancement of chromaticaberrations, which has increased a cost. On the other hand, the imagepickup lenses proposed in Patent Literature 3 to 7 with considerationfor mass-productivity have exhibited a large F-number. Therefore, whentrying to cope with a fine pixel pitch, they have caused increased noiseand their performance has become insufficient to cope with an increasednumber of pixels.

The invention has been achieved in view of the aforesaid situations, andits object is to provide an image pickup lens which can be mass-producedat a low cost, with keeping a small F-number and high opticalperformance so as to cope with a fine pixel pitch of an image pickupelement, and to provide an image pickup apparatus equipped with the sameand a mobile terminal.

Solution to Problem

The above object is achieved by the following structures.

1. An image pickup lens comprising four or more lens blocks, whereineach of the lens blocks is assumed to be an optical element comprising alens substrate being a parallel flat plate, and a lens portion or lensportions having positive or negative power and formed on at least one ofan object-side surface and image-side surface of the lens substrate, andthe lens substrate is different in material from the lens portion orlens portions, the image pickup lens being characterized in that, whenthe lens blocks are assumed to be, in order from an object side, a firstlens block, a second lens block, a third lens block, and a fourth lensblock, the first lens block has positive power, the second lens blockhas negative power, and a lens block arranged at a closest position toan image side has a concave shape facing the image side in a paraxialregion, at least one of lens portions each having a concave shape in theparaxial region satisfies the following conditional expression (1), andthe first lens block satisfies the conditional expression (3):

νn<40  (1)

0.5<f1/f<1.5  (3)

where νn is an Abbe number of a lens portion having a concave shape inthe paraxial region, f1 is a composite focal length of the first lensblock, and f is a composite focal length of a total system.

2. The image pickup lens of Item 1, characterized in that the at leastone of lens portions satisfying the conditional expression (1) satisfiesthe conditional expression (2):

0.5<|m/f|<1.0  (2)

where m is a curvature radius of the surface having a concave shape inthe paraxial region, and f is the composite focal length of the totalsystem.

3. The image pickup lens of Item 1 or 2, characterized by comprising astop arranged at a closer position to the object side than the secondlens block.

4. The image pickup lens of any one of Items 1 to 3, characterized bysatisfying the following conditional expression (3a):

0.7<f1/f<1.2  (3a)

where f1 is a composite focal length of the first lens block, and f isthe composite focal length of the total system.

5. The image pickup lens of any one of Items 1 to 4, characterized bysatisfying the following conditional expression (4):

−2.5<f2f<−0.9  (4)

where f2 is a composite focal length of the second lens block, and f isthe composite focal length of the total system.

6. The image pickup lens of any one of Items 1 to 5, characterized inthat

the second lens block has a convex shape facing the image side in theparaxial region.

7. The image pickup lens of any one of Items 1 to 6, characterized bysatisfying the following conditional expression (5):

0.8<|f3/f|<3.0  (5)

where f3 is a composite focal length of the third lens block, and f isthe composite focal length of the total system.

8. The image pickup lens of any one of Items 1 to 7, characterized inthat the third lens block has a concave shape facing the image side inthe paraxial region.

9. The image pickup lens of any one of Items 1 to 8, characterized inthat a rearmost lens surface includes an inflection point.

10. The image pickup lens of any one of Items 1 to 9, characterized bybeing a four-block structure.

11. The image pickup lens of Item 10, characterized in that the fourthlens block has negative power.

12. The image pickup lens of any one of Items 1 to 11, characterized bysatisfying the following conditional expression (6):

(D1a+D2a+D3a)/f<0.35  (6)

where D1a is a distance along an optical axis between the first lensblock and the second lens block,

D2a is a distance along the optical axis between the second lens blockand the third lens block,

D3a is a distance along the optical axis between the third lens blockand the fourth lens block, and

f is the composite focal length of the total system.

13. The image pickup lens of any one of Items 1 to 12, characterized inthat all of the lens substrates are parallel flat plates having a samethickness.

14. The image pickup lens of any one of Items 1 to 13, characterized inthat each of the lens substrates is formed of a glass material.

15. The image pickup lens of any one of Items 1 to 14, characterized inthat each of the lens portions is formed of a resin material.

16. The image pickup lens of Item 15, characterized in that the resinmaterial is an energy-curable resin material.

17. The image pickup lens of Item 15 or 16, characterized in thatinorganic particles with a size of 30 nanometers or less are dispersedin the resin material.

18. The image pickup lens of any one of Items 1 to 17, characterized inthat the lens blocks are manufactured by a manufacturing processcomprising: a step of sealing an area between the lens substrates with aspacer member formed in a grid shape; and a step of cutting the lenssubstrates and the spacer member which have been joined together, alonga framework of a grid of the spacer member.

19. An image pickup apparatus characterized by comprising: the imagepickup lens of any one of Items 1 to 18; and an image pickup element forconverting an optical image formed on an light-receiving surface intoelectric signal, wherein the image pickup lens is arranged so as to forman optical image of a subject on the light-receiving surface of theimage pickup element.

20. A mobile terminal characterized by comprising the image pickupapparatus of Item 19.

Advantageous Effects of Invention

According to the present invention, an image pickup lens which can bemass-produced at a low cost with keeping a small F-number and highoptical performance so as to cope with a fine pixel pitch of an imagepickup element, image pickup apparatus equipped with the same, and amobile terminal can be realized.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an optical construction diagram of the first embodiment(Example 1).

FIG. 2 is an optical construction diagram of the second embodiment(Example 2).

FIG. 3 is an optical construction diagram of the third embodiment(Example 3).

FIG. 4 is an optical construction diagram of the fourth embodiment(Example 4).

FIG. 5 is an optical construction diagram of the fifth embodiment(Example 5).

FIG. 6 is an optical construction diagram of the sixth embodiment(Example 6).

FIG. 7 is an optical construction diagram of the seventh embodiment(Example 7).

FIG. 8 is an optical construction diagram of the eighth embodiment(Example 8).

FIG. 9 is an optical construction diagram of the ninth embodiment(Example 9).

FIG. 10 is an optical construction diagram of the tenth embodiment(Example 10).

FIG. 11 shows aberration diagrams of Example 1.

FIG. 12 shows aberration diagrams of Example 2.

FIG. 13 shows aberration diagrams of Example 3.

FIG. 14 shows aberration diagrams of Example 4.

FIG. 15 shows aberration diagrams of Example 5.

FIG. 16 shows aberration diagrams of Example 6.

FIG. 17 shows aberration diagrams of Example 7.

FIG. 18 shows aberration diagrams of Example 8.

FIG. 19 shows aberration diagrams of Example 9.

FIG. 20 shows aberration diagrams of Example 10.

FIG. 21 is a diagram showing an example of a schematic construction of amobile terminal equipped with an image pickup apparatus, by using aschematic sectional view.

FIG. 22 is a schematic sectional view showing an example ofmanufacturing steps of an image pickup lens.

DESCRIPTION OF EMBODIMENTS

An image pickup lens, image pickup apparatus and mobile terminalrelating to the present invention will be described below, withreferring to the drawings. The image pickup lens relating to the presentinvention comprises four or more of lens blocks. Herein, a “lens block”means an optical element composed of a lens substrate being a parallelflat plate, and of a lens portion or lens portions with positive ornegative power formed on at least one of the object-side surface and theimage side surface of the lens substrate. The lens substrate and thelens portion or lens portions which are considered in this description,are formed of different materials.

Since the image pickup lens includes four or more lens blocks asdescribed above, under the assumption that a lens block at the i-thposition (i=1, 2, . . . ) in order from the object side to the imageside, is defined as an i-th lens block, the image pickup lens includesat least the first lens block, the second lens block, the third lensblock, and the fourth lens block, which are arranged in this order fromthe object side. The first lens block has positive power and the secondlens block has negative power. The lens block arranged at the closestposition to the image side has a concave shape facing the image side inthe paraxial region. At least one of lens portions each having a concaveshape in the paraxial region satisfies the following conditionalexpression (1), and the first lens block satisfies the followingconditional expression (3).

νn<40  (1)

0.5<f1/f<1.5  (3)

In these expressions, νn is an Abbe number of a lens portion having aconcave shape in the paraxial region, f1 is a composite focal length ofthe first lens block, and f is a composite focal length of the totalsystem.

When strong positive power is distributed to the first lens block sothat the first lens block may satisfy the conditional expression (3),the length of the total system can be shortened while excellent opticalperformances are maintained. When the value of the conditionalexpression (3) becomes larger than the lower limit, the first lens blockdoes not have excessively strong power, and various aberrations such asspherical aberration, field curvature, astigmatism, and distortion canbe controlled to be small. Further, it provides an optical system withless deterioration of performance even when the first lens block isdecentered. On the other hand, when the value of the conditionalexpression (3) becomes smaller than the upper limit, the first lensblock does not have excessively weak power, and the length of the totalsystem does not become excessively large.

Further, when at least one of lens portions each having a concave shapein the paraxial region satisfies the following conditional expression(1), chromate aberrations can be effectively controlled to be small.Even when a conventional wafer-scaled lens having a two-block orthree-block structure employs a lens portion satisfying the conditionalexpression (1) to achieve the same level of achromatism as that of afour-block structure, the optical system including the first lens blockwith strong positive power naturally requires an arrangement of at leastone lens with negative power to make the Petzval sum small. When suchthe arrangement is employed in a structure with a smaller number of lensblocks, the system naturally has a power arrangement of a typicaltelephoto system, which disagrees with the demand to achieve a wideangle in an image pickup lens to be mounted in a mobile terminal.Therefore, in the present invention, the system includes at least fourlens blocks and positive power of the first lens block and negativepower of the second lens block are shared with the other lens blocks.

Sequentially from the first lens block at the closest to the objectside, the system has a structure that the first lens block has positivepower to deflect a ray so as to make the ray enter the second lens blockwith negative power, which allows the negative power of the second lensblock to be strong and makes spherical aberration, astigmatism, andPetzval sum effectively small. When the third lens block has positivepower, the negative power of the second lens block can be strengthenedwhile the positive power of the total system of the image pickup lens ismaintained, which decreases spherical aberration, astigmatism, andPetzval sum more effectively. Alternatively, when the third lens blockhas negative power, Petzval sum can be reduced, too. Accordingly, thethird lens block with any power can be intended to enhance theperformance.

The structure that a lens block arranged at the closest position to animage side has a concave shape facing the image side, means that a lensportion formed on the image-side surface of a lens substrate has animage-side surface in a concave shape, in the lens block at the closestposition to the image side. When the image-side surface of the lensblock arranged at the closest position to the image side has a concaveshape, a lens back is easily secured. A situation that an image pickupelement and an image pickup lens conflict with each other and are hardlyassembled, because of fluctuation of a back focal length caused byerrors in a concentric optical system, can be avoided by employing thisstructure, which enables to achieve a compatibility of downsizing thetotal length and maintaining the sufficient back focal length.

Due to the above matters, even the structure with the small-sized totallength and the reduced number of blocks such as four blocks, can copewith a small F-number and the increased number of pixels by correctingvarious aberrations to be an excellent condition.

In the present invention, it is preferable that there is provided atleast one lens composed of a lens portion in a convex shape having a lowdispersion and a lens portion in a concave shape having a highdispersion within the range determined by the conditional expression (1)in the same lens block. Thereby, chromatic aberrations can be correctedin one lens block and chromatic aberrations can be effectively correctedwithout losing an ability of correcting the other various aberrations.

Even when a small F-number is achieved by the above structure, there isa tendency that sensitivity to a manufacturing error becomes large, as aresult of being combined with an effect of downsizing of a pixel pitch.Therefore, lens portions are arranged on a lens substrate being aparallel flat plate so as to realize the reduction of tilt decentrationcaused in an assembling process by using the advantage of accuracy ofthe parallel flat plate in shape. Because a parallel flat plate isobtained by being cut out from quite larger member than the lensportions, unevenness of each lens in shape can be controlled to besmaller than small lenses. Further, because it can be cut out afterplural lens portions are arranged on one large parallel flat plate,adjustment of shift decentration is not required for individual lenses.A shift decentration in several lenses among all the lenses is adjustedby adjusting each lens substrate as a parallel flat plate. Thereby, theshift decentration can be minimized in each lens. Accordingly, even whenthe sensitivity to manufacturing error is high because of providingsmall-sized pixel pitch and small F-number and of employing a largenumber of lenses such that four or more lenses, mass production can beachieved with high accuracy at a low cost.

According to the above characterized structures, there can be realizedan image pickup lens and an image pickup apparatus equipped with thesame, where the image pickup lens has a high optical properties and canbe mass-produced at a low cost even if its F-number is made to be smallin order to employ an image pickup element with a fine pixel pitch. Whenthe image pickup apparatus equipped with the image pickup lens is usedfor a digital device such as a mobile terminal, it can contribute todownsizing, saving cost, and enhancement of performance. Conditions forobtaining such the effects in a balanced condition and for achievinghigher optical performance and smaller size of the total system will bedescribed below.

It is more preferable that the following conditional expression (1a) issatisfied.

νn<35  (1a)

The conditional expression (1a) defines a more preferable conditionalrange based on the above view points, out of the conditional rangedefined by the conditional expression (1).

It is preferable that the at least one of lens portions satisfying theconditional expression (1) satisfies the conditional expression (2).

0.5<|m/f|<1.0  (2)

In the expression, m is a curvature radius of a surface having a concaveshape in the paraxial region, and f is a composite focal length of thetotal system.

When the value of the conditional expression (2) becomes larger than thelower limit, the curvature does not become excessively great anddecentration sensitivity of the lens surface can be reduced. On theother hand, when the value of the conditional expression (2) becomessmaller than the upper limit, chromatic aberrations can be reducedeffectively.

It is more preferable that the following conditional expression (2a) issatisfied.

0.5<|m/f|<0.8  (2a)

The conditional expression (2a) defines more preferable conditionalrange based on the above view points, out of the conditional rangedefined by the conditional expression (2). When the value of theconditional expression (2a) becomes smaller than the upper limit,chromatic aberrations can be reduced more effectively.

It is furthermore preferable that the following conditional expression(2b) is satisfied.

0.5<|m/f|<0.7  (2b)

The conditional expression (2b) defines further more preferableconditional range based on the above view points, out of the conditionalrange defined by the conditional expression (2). When the value of theconditional expression (2b) becomes smaller than the upper limit,chromatic aberrations can be reduced furthermore effectively.

There is preferably provided a stop arranged at a closer position to theobject side than the second lens block. When a stop is arranged at acloser position to the object side than the second lens block, the stopcan be separated away from the image plane and the telecentricity can beenhanced.

The stop is preferably positioned on the lens substrate in the firstlens block. The condition that the stop is positioned on the lenssubstrate in the first lens block means that the stop is arranged insidethe lens. Thereby, unwanted light which is generated when light reflectsat the outside of the effective aperture of the lens portion arranged ata closer position to the object side than the stop, can be eliminatedeffectively. The stop to be arranged may be a molded plate formed ofresin or glass, or may be formed by coating a lens substrate with adielectric material.

The stop is preferably positioned on the object-side surface of the lenssubstrate in the first lens block. When the stop is positioned on theobject-side surface of the lens substrate in the first lens block,unwanted light can be blocked and the telecentricity can be enhanced atthe same time, because the stop can be separated away from the imageplane.

It is preferable that the following conditional expression (3a) issatisfied and it is more preferable that the following conditionalexpression (3b) is satisfied.

0.7<f1/f<1.2  (3a)

0.8<f1/f<1.1  (3b)

These conditional expressions (3a) and (3b) define more preferableconditional ranges based on the above view points, out of theconditional range defined by the conditional expression (3). Forexample, when the value of the conditional expressions (3a) becomeslarger than the lower limit, the power of the first lens block does notbecome excessively strong and various aberrations such that sphericalaberration, field curvature, astigmatism, and distortion can becontrolled to be small. Further, there can be provided an optical systemwith less deterioration of performance even when the first lens block isdecentered. On the other hand, when the value of the conditionalexpression (3a) becomes smaller than the upper limit, the first lensblock does not have excessively weak power, and the length of the totalsystem does not become excessively large. When the conditionalexpression (3b) is satisfied, the above matters become more effective.

It is preferable that the following conditional expression (4) issatisfied.

−2.5<f2/f<−0.9  (4)

In the expression, f2 is a composite focal length of the second lensblock, and f is a composite focal length of the total system.

When the value of the conditional expression (4) becomes larger than thelower limit, Petzcal sum is prevented to be excessively large and thegeneration of curvature field can be reduced. On the other hand, whenthe value of the conditional expression (4) becomes smaller than theupper limit, the power of the second lens block does not becomeexcessively strong, and there can be provided an optical system withless deterioration of performance even when the second lens block isdecentered.

It is preferable that the second lens block has a convex shape facingthe image side in the paraxial region. When the second lens block has aconvex shape facing the image side in the paraxial region, the positionof the principal point of the second lens block can be separated awayfrom the first lens block, and the power of the first lens block and thepower of the second lens block can be reduced. In the present invention,the first lens block and the second lens block have a tendency to makethe deterioration of performance large because of their decentration,compared with the other lens blocks. Therefore, the optical system withsmall deterioration of performance can be obtained effectively.

It is preferable that the second lens block has a meniscus shape whoseconvex surface faces the image side in the paraxial region. When thesecond lens block has a meniscus shape, the position of the principalpoint of the second lens block can be separated further away from thefirst lens block, and the power of the first lens block and the power ofthe second lens block can be reduced. Thereby, the optical system withmuch less deterioration of performance can be obtained, even when thefirst lens block and the second lens block are decentered.

It is preferable that the following conditional expression (5) issatisfied.

0.8<|f3/f3.0  (5)

In the expression, f3 is a composite focal length of the third lensblock, and f is a composite focal length of the total system.

When the value of the conditional expression (5) becomes larger than thelower limit, the power of the third lens block does not becomeexcessively large, which provides a lens with small decentration ofperformance when the third lens block is decentered. On the other hand,when the value of the conditional expression (5) becomes smaller thanthe upper limit, the power of the third lens block does not becomeexcessively weak, and various aberrations can be corrected in anexcellent condition.

It is preferable that the third lens block has a concave shape facingthe image side in the paraxial region. When the third lens block has aconcave shape facing the image side in the paraxial region, the backfocal length is easily secured. Even when the fourth lens block isarranged, the enough back focal length can be secured.

It is preferable that the image-side surface of the third lens block hasa concave shape facing the image side in the paraxial region and thesurface includes an inflection point. When the image-side surface of thethird lens block includes an inflection point, it makes a light flux tobe formed into an image on a periphery of the image area, enter the lenssurface at an almost right angle. Thereby, generation of variousaberrations can be reduced.

It is preferable that the rearmost lens surface includes an inflectionpoint, and is more preferable that the rearmost lens surface has aconcave shape in the paraxial region. When the rearmost lens surfaceforms a concave shape in the paraxial region and has an inflectionpoints in the peripheral region, the lens surface can provide adivergent action to a ray around the paraxial region and provide aconvergent action to an off-axis ray to be formed into an image in theperiphery of an image pickup element. Thereby, the telecentricity in theperipheral region of the image area can be enhanced with the enough backfocal length being secured.

It is preferable that the image pickup lens is a four-block structure.When forming the image pickup lens as a four-block structure, downsizingof the total length and reduction of sensitivity of respective lensblocks to manufacturing error can be balanced in an excellent condition.If the image pickup lens is tried to be constructed as a three-blockstructure, it leads to downsizing of the total length but burden ofpower on each lens becomes large, which increase the sensitivity tomanufacturing error. On the other hand, if the image pickup lens istried to be constructed as a five or more block structure, its power canbe shared by respective lenses and the sensitivity to manufacturingerror can be reduced. However, the total length becomes large.

It is preferable that the fourth lens block has negative power in theimage pickup lens as a four-block structure. When the lens blockarranged at the closest position to an image pickup element has negativepower, the back focal length can be elongated with its effect to aspherical aberration being minimized. When a negative power is arrangedclose to an image pickup element, it can make the height of a paraxialray low. Further, it does not affect the power of the total system andthe spherical aberration but Petzval sum can be reduced.

It is preferable that the following conditional expression (6) issatisfied.

(D1a+D2a+D3a)/f<0.35  (6)

In the expression, D1a is a distance along an optical axis between thefirst lens block and the second lens block, D2a is a distance along theoptical axis between the second lens block and the third lens block, D3ais a distance along the optical axis between the third lens block andthe fourth lens block, and f is a composite focal length of the totalsystem.

When the conditional expression (6) is satisfied, the content amount ofgas existing between lenses can be reduced, which can reduce the rise ofatmospheric pressure caused by expansion of the gas, even when thesurrounding temperature rises and can reduce the risk of damage.

It is more preferable that the following conditional expression (6a) issatisfied.

(D1a+D2a+D3a)/f<0.30  (6a)

The conditional expression (6a) defines more preferable conditionalrange based on the above view points, out of the conditional rangedefined by the conditional expression (6). When the conditionalexpression (6a) is satisfied, the content amount of gas existing betweenlenses can be furthermore reduced, which can furthermore reduce the riseof atmospheric pressure caused by expansion of the gas even when thesurrounding temperature rises and can furthermore reduce the risk ofdamage.

It is preferable that all of the lens substrates are parallel flatplates having the same thickness. When all of the lens substrates areparallel flat plates having the same thickness, processing andassembling become easy. Because all the lens substrates have no power atthe boundary between them and the lens portions, affection of a surfaceaccuracy to the focal point position on the image plane can be reduced.

It is preferable that each of the lens subs aces is formed of a glassmaterial. Glass has a higher softening temperature than that of resin.Therefore, when lens substrates are formed of glass, they are notdeteriorated easily even when a reflow processing is performed, and thecost can be reduced. It is more preferable that lens substrates areformed of glass with high softening temperature. When the materialemployed for the lens substrate is glass, a deterioration of opticalproperties (such as birefringence inside a lens) caused by a straincaused inside a lens can be reduced better than resin.

It is preferable that each of the lens portions is formed of a resinmaterial. As a material employed for the lens portions, a resin materialis more excellent in terms of a property of processing and molding thana glass material and the cost can be reduced.

It is preferable that the resin material is an energy-curable resinmaterial. When the lens portions are formed of energy-curable resinmaterial, the large number of lens portions can be formed by beinghardened on a wafer-shaped lens substrate with a mold at the same time.Accordingly, it can enhance a mass-productivity. An energy-curable resinmaterial in this description means a material such as a resin materialhardened by heat, and a resin material hardened by light Various meansso as to provide energy such as heat and light can be used for thehardening process.

It is preferable that UV-curable resin material is used as theenergy-curable resin material. When the UV-curable resin material isused, mass-productivity can be enhanced because the hardening timebecomes short. Further, curable resins with excellent heat resistancehave been recently developed. When a resin material with heat resistanceis employed, it can cope with a camera module which stands for a reflowprocessing and more inexpensive camera module can be provided. Thereflow processing in this description, means a processing that solder asa paste is printed on a printed board (circuit board), heat is added tothe printed board to melt the solder after components (camera module)are put on it, and external terminals of sensors are welded to thecircuit board automatically.

It is preferable that inorganic particles having a size of 30 nanometersor less are dispersed in the resin material. When inorganic particleshaving a size of 30 nanometers or less are dispersed in a lens portionformed of a resin material, deterioration of performance and fluctuationof image point position can be reduced even when a temperature changes.Further, there can be obtained an image pickup lens having excellentoptical properties despite of environmental change without lowering oflight transmittance. In general, if fine particles are mixed in atransparent resin material, light scatters therein and it causes loweredtransmittance. Therefore, it has been difficult to use such a materialas an optical material. However, by making a size of microparticles tobe smaller than a wavelength of a transmitting light flux, occurrence oflight scattering can be prevented substantially.

Further, though it has been a drawback of resin material that itsrefractive index is lower than that of glass material, it has found thatthe refractive index can be made to be high, by dispersing inorganicparticles having high refractive index in a resin material representingbase material. Specifically, it is possible to offer a material havingan arbitral refractive index, by dispersing inorganic particles of asize of 30 nanometer or less, preferably of 20 nanometer or less, morepreferably 15 nanometer or less, into a resin material serving as a basematerial.

The refractive index of a resin material is lowered if a temperaturerises. However, it has been known that, when there are preparedinorganic particles whose refractive index rises if a temperature rises,and when the inorganic particles are dispersed in the resin materialserving as a base material, properties of both parties act on each otherto cancel, thus, fluctuations of refractive index for temperaturechanges can be made small. Further, on the contrary, it has also beenknown that, when there are prepared inorganic particles whose refractiveindex declines if a temperature rises, and when the inorganic particlesare dispersed in the resin material serving as a base material,fluctuations of refractive index for temperature changes can be made tobe large. Specifically, it is possible to offer materials havingarbitral temperature-dependency, by dispersing inorganic particles of aparticle size of 30 nanometer or less, preferably 20 nanometer or less,more preferably 15 nanometer or less, into a resin material serving as abase material. For example, when inorganic particles such as aluminumoxide (Al₂O₃) and lithium niobate (LiNbO₃) are dispersed in an acrylicresin, it is possible to obtain a resin material having high refractiveindex and to make fluctuations of changes in refractive index fortemperature changes to be small.

Next, refractive index change A due to temperature will be explained indetail as follows. The refractive index change A due to temperature isexpressed by the following expression (FA) by differentiating arefractive index “n” with respect to temperature “t”, based onLorentz-Lorenz equation.

$A = {\frac{\left( {n^{2} + 2} \right)\left( {n^{2} - 1} \right)}{6n}\left\{ {\left( {{- 3}\alpha} \right) + {\frac{1}{\lbrack R\rbrack}\frac{\partial\lbrack R\rbrack}{\partial t}}} \right\}}$

. . . (FA)

In the expression (FA), α represents the coefficient of linearexpansion, and [R] represents molecular refraction.

In the case of resin materials, a contribution of the second term to therefractive index change is generally smaller than that of the first termin the expression (FA), and it can be mostly neglected. For example, inthe case of PMMA (polymethyl methacrylate) resins, coefficient of linearexpansion α is 7×10⁻⁵. When it is substituted in the aforesaidexpression (FA), dn/dt=−1.2×[/° C.] holds to almost agree with actualmeasurements.

In this case, by dispersing fine particles, which are preferablyinorganic materials, in a resin material, the contribution of the secondterm in the aforesaid expression (FA) is made to be substantially largeso that it may offset with a change by linear expansion of the firstterm each other. Specifically, it is desirable that the change which hasbeen about −1.2×10⁻⁴ is controlled to be less than 8×10⁻⁵ in an absolutevalue. It is further possible to exhibit a temperature dependency whichis opposite to that of a resin material representing a base material, byfurther increasing the contribution of the second term. In other words,it is also possible to obtain a raw material whose refractive index israised rather than declined when temperature rises. A mixing ratio ofthe particles can be varied properly for controlling a change rate of areflective index for temperature, and it is also possible to disperseinorganic particles such that plural types of particles in nano-sizesare blended.

It is preferable that, in an image pickup lens, the lens blocks aremanufactured by a manufacturing process comprising: a step of sealing anarea between the lens substrates with a spacer member formed in a gridshape; and a step of cutting the lens substrates and the spacer memberwhich have been joined together, along a framework of a grid of thespacer member. For example, an image pickup lens in which all the lensesare formed by lens blocks, can be easily manufactured by a manufacturingmethod for manufacturing plural image pickup lenses for forming an imageof a subject and plural image pickup apparatuses including the imagepickup lenses, comprising a step of sealing an area between the lenssubstrates with a spacer member formed in a grid shape; and a step ofcutting the lens substrates and the spacer member which have been joinedtogether, along a framework of a grid of the spacer member. Thereby,inexpensive image pickup lenses can be mass-produced.

As a manufacturing method of manufacturing plural image pickup lenses,for example, a reflow processing or a replica processing is employed. Asfor the reflow method, glass having a low softening temperature isdeposited through a CVD (Chemical Vapor Deposition) method, theresulting glass is processed through lithography and through dryetching, and the glass-reflow processing is carried out by using a heatprocessing. Thereby, a large number of lenses are manufacturedsimultaneously on a glass substrate. As for the replica method, a largenumber of lenses are manufactured simultaneously on a glass substrate bytransferring a large number of lens shapes simultaneously on a lenswafer with a mold by using a curable resin. A large number of lenses canbe formed at the same time with any of the methods, and the cost can bereduced. For example, when there are prepared different lensesmanufactured by the above method (two lenses prepared by forming lensportions on a lens substrate and cutting the lens substrate into pieces,and their lens portions are different from each other) and when theirflat plate portion are adhered together, it forms a lens block in whichthe first lens portion, the first parallel flat plate, the secondparallel flat plate, and the second lens portion are arranged in thisorder.

FIG. 22 shows an example of manufacturing steps of an image pickup lensby using a schematic sectional view. In the followings, them is given anexample of a two-block structure, in order to simplify the description.However, an image pickup lens formed of four or more blocks can bemanufactured similarly. First lens block C1 is composed of first lenssubstrate L12 formed of a parallel flat plate, plural 1a-th lensportions L11 adhered on one plane of it, and plural 1b-th lens portionsL13 adhered on the other plane. The first lens substrate L12 may becomposed of a single parallel flat plate, or may be composed of twoparallel flat plates joined together as described above. Second lensblock C2 is composed of second lens substrate L22 formed of a parallelflat plate, plural 2a-th lens portions L21 adhered on one plane of it,and plural 2b-th lens portions L23 adhered on the other plane. Similarlyto the first lens substrate L12, the second lens substrate L22 may becomposed of a single parallel flat plate, or may be composed of twoparallel flat plates joined together as described above.

Spacer member B1 in a grid shape lies between the first lens block C1and the second lens block C2 to keep a distance between them to beconstant, and forms a two-tier structure. Lens portions are arranged inholes of the grid. Substrate B2 is a parallel flat plate (whichcorresponds to parallel flat plate PT in FIG. 21) such as a wafer-levelchip-size package for a sensor including a microlens array, and aparallel flat plate such as a sensor cover glass and an infraredblocking filter. When a space between the lens substrates (namely, thefirst lens substrate L12 and the second lens substrate L22) is sealedwith the spacer member B1 on the substrate B2, and when the first andsecond lens substrates L12 and L22 and the spacer member B1 joinedtogether are cut along the framework of the gird of the spacer member B1(along the position of the broken lines Q), plural image pickup lenseseach formed of two elements can be obtained. As described above, becausea body in which plural first and second lens blocks C1 and C2 areassembled is cut into image pickup lenses, it does not require anadjustment of a lens distance and an assembling process for each imagepickup lens, which enables mass production. Further, because the spacermember B1 is formed in a grid shape, it can be used for a mark for thecutting process. It is consistent with the object in the presenttechnical art, and contributes to mass production of inexpensive lenssystems.

An image pickup lens relating to the present invention is suitable to beused for a digital device with an image inputting function (for example,a mobile terminal). When the image pickup lens is combined with a devicesuch as an image pickup element, it can construct an image pickupapparatus which takes an image of a subject therein in an optical mannerand outputs it as electric signal. The image pickup apparatus is anoptical device forming an essential construction part of a camera usedfor shooting a static image or movie of a subject. For example, theimage pickup apparatus is composed of, in order from an object (namely,a subject), an image pickup lens for forming an optical image of thesubject, and an image pickup element for converting the optical imageformed by the image pickup lens into electric signal. By arranging theimage pickup lens with the above-described features is arranged so as toform the optical image of the subject on a light-receiving surface ofthe image pickup element, an image pickup apparatus with highperformance and a digital device equipped with the same (for example, amobile terminal) can be realized at a low cost.

As an example of a camera, a digital camera, a video camera, a securitycamera, an on vehicle camera and a videophone camera are cited. Further,the camera may also be built in or be attached on a personal computer, amobile terminal (for example, a compact and portable informationequipment terminal such as a cell-phone and a mobile computer), aperipheral of the aforesaid equipment (a scanner and a printer or thelike) and other digital equipment. As is understood from these examples,loading of an image pickup apparatus constructs not only a camera butalso various types of equipment having functions of a camera. Forexample, a digital equipment having an image inputting function such asa cell-phone equipped with a camera can be constructed.

FIG. 21 shows a diagram of an example of a schematic construction of amobile terminal CU as an example of a digital apparatus with an imageinputting function, by using a schematic sectional view. Image pickupapparatus LU mounted in the mobile terminal CU in FIG. 21 includes, inorder from the object (namely subject) side, image pickup lens LN forforming optical image (image plane) IM of the object (where AXrepresents an optical axis), parallel flat plate PT (equivalent to anoptical filter arranged depending on the situation, such as an opticallow-pass filter and infrared cut filter; and to a cover glass of imagepickup element SR), and image sensor SR for converting optical image IMformed on light-receiving surface SS formed by image pickup lens LN intoelectric signal. When mobile terminal CU having an image inputtingfunction is composed of image pickup apparatus LU of this kind, imagepickup apparatus LU is generally arranged in the inside of a body of themobile terminal CU. For realizing camera functions by mobile terminalCU, image pickup apparatus LU can take a form that is required. Forexample, unitized image pickup apparatus LU may be mounted on ordismounted from a main body of mobile terminal CU freely, or it may befreely rotatable for a main body of mobile terminal CU.

For example, as image pickup element SR, there are given an image sensorof a CCD type and an image sensor of a CMOS type both having a pluralityof pixels thereon. The image pickup lens LN is positioned so thatoptical image IM of a subject may be formed on light-receiving surfaceSS of image sensor SR. Therefore, optical image IM formed by the imagepickup lens LN is converted efficiently into electric signal.

Mobile terminal CU includes signal processing section 1, control section2, memory 3, operation section 4 and display section 5, in addition tothe image pickup apparatus LU. The signal processing section 1 conducts,for example, prescribed digital image processing and image compressionprocessing, for signal generated by image sensor SR, as occasiondemands. Then, the processed signal is recorded in memory 3 (such assemiconductor memory and optical disc) as digital image signal, or istransmitted to the other equipment by passing through cables or beingconverted into infrared radiation signal. The control section 2 isformed of a microcomputer and intensively carries out a control forimage pickup function and image reproducing function, and a control of alens drive mechanism for a focusing operation. For example, the controlsection 2 controls image pickup apparatus LU so that at least one ofshooting still images of a subject and shooting video of a subject maybe carried out. The display section 5 is a portion including a displaysuch as a liquid crystal monitor, and it displays images by using imagesignal converted by image sensor SR or by using image informationrecorded in memory 3. The operation section 4 is a portion includingoperating members such as an operation button (for example, a releasebutton) and an operation dial (for example, a shooting mode dial), andit transmits information operated and inputted by an operator to thecontrol section 2.

Image pickup lens LN includes four or more lens blocks as describedbelow, and has a structure to form optical image IM on light-receivingsurface SS of image pickup element SR. An optical image to be formed bythe image pickup lens LN passes through, for example, an opticallow-pass filter (corresponding to parallel flat plate PT in FIG. 21)having a predetermined cut-off frequency characteristic determined by apixel pitch of image pickup element SR. Its spatial frequencycharacteristic is adjusted so that a so-called folding noise generatedwhen an image is converted into electric signal may be minimized toafter this passage. Thereby, occurrence of color moiré can becontrolled. However, if a performance at a frequency around theresolution limit has been controlled, noises are not generated even whenan optical low-pass filter is not used. Further, when a user takes orviews a photograph by using a display system having a less noise (forexample, a liquid crystal screen of a cell-phone), no optical low-passfilter is needed.

As for focusing operation of image pickup lens LN, the whole of lensunit may be moved in the direction of optical axis AX with an actuator,or a part of lenses may be moved in the direction of optical axis AX.For example, when the focusing operation is carried out by using onlythe first lens block C1, the actuator can be downsized. Further, thefocusing function may be realized by carrying out the processing to makethe depth of focus deeper with software by using information recorded onimage pickup element SR, rather than by moving the lens in the directionof the optical axis for the focusing operation. In that case, theactuator is not required, which realizes downsizing and saving cost atthe same time.

Next, a specific optical structure of image pickup lens LN will bedescribed with giving the first to tenth embodiments. FIGS. 1 to 10 showlens structures of the first to tenth embodiments as optical sectionaldiagrams, respectively. Image pickup lens LN of each embodiment is asingle-focus lens for shooting (for example, for a mobile terminal) toform optical image IM for image pickup element SR, as shown in FIG. 21.In the first to tenth embodiments, image pickup lens LN is composed offour lens blocks including, in order from the object side, first lensblock C1, second lens block C2, third lens block C3, and fourth lensblock C4.

In the first to tenth embodiments, lens blocks C1 to C4 are formed asfollows, in order from the object side. In the first lens block C1, lathlens portion L11, first lens substrate L12, and 1b-th lens portion L13are arranged in this order. In the second lens block C2, 2a-th lensportion L21, second lens substrate L22, and 2b-th lens portion L23 arearranged in this order. In the third lens block C3, lens 3a-th sectionL31, third lens substrate L32, and 3b-th lens portion L33 are arrangedin this order. In the fourth lens block C4, 4a-th lens portion L41,fourth lens substrate L42, and 4b-th lens portion L43 are arranged inthis order. When an i-th (where i=1, 2, 3, and 4) positioned lens blockfrom the object side to the image side is assumed to be i-th lens blockCi, the ia-th lens block Li1 and the i-th lens substrate Li2 havedifferent refractive indexes, and the i-th lens substrate Li2 and theib-th lens block Li3 have different refractive indexes.

In the first, second, fourth, sixth, and seventh embodiments, the powerarrangement of lens blocks C1 to C4 is in order of positive, negative,positive, and negative. In the third, fifth, ninth, and tenthembodiments, the power arrangement of lens blocks C1 to C4 is in orderof positive, negative, positive, and positive. In the eighth embodiment,the power arrangement of lens blocks C1 to C4 is in order of positive,negative, negative, and positive. In each embodiment, a powerarrangement of positive and negative is positioned at the most closestposition to the object side. Therefore, the above-described effect tocorrect aberrations can be obtained. In the first, second, fourth,sixth, and seventh embodiments, the fourth lens block C4 which is at theclosest position to the image side has negative power, which reducesinfluence to the spherical aberration as described above as much aspossible and elongates the back focal length.

In the first to tenth embodiments, the fourth lens block C4 has aconcave shape facing the image side. In other words, the image-sidesurface of 4b-th lens portion L43 has a concave shape in the paraxialregion. Thereby, an effect that the back focal length is easily securedis obtained as described above. Further, the image-side surface of 4b-thlens portions L43, which is the rearmost lens surface, includes aninflection point in the lens periphery. Thereby, the surface has adivergent action for rays around the paraxial region, and also has aconvergent action for off-axis rays to be formed on the periphery of theimage pickup element. Thereby, telecentricity can be enhanced in theperiphery of the image area with a sufficient back focal length beingsecured.

In the second, third, sixth to eighth, and tenth embodiments, the secondlens block C2 has a convex shape facing the image side in the paraxialregion. In other words, the image-side surface of 2b-th lens portion L23has a convex shape in the paraxial region. Thereby, a deterioration ofperformance can be reduced as described above, even when the first andsecond blocks C1 and C2 are decentered. Because the second lens block C2in these embodiments has a meniscus shape, the effect to be obtainedbecomes greater.

In the first to third and fifth to tenth embodiments, the third lensblock C3 has a concave shape facing the image side in the paraxialregion. In other words, the image-side surface of 3b-th lens portion L33has a concave shape in the paraxial region. Thereby, an effect that theback focal length can be easily maintained can be obtained as describedabove. Because the image-side surface of 3b-th lens portion L33 includesan inflection point, an effect to reduce a generation of variousaberrations as described above is also obtained.

In the first, second, fourth to eighth embodiments, there is arrangedaperture stop ST on the object-side surface of the first lens substrateL12 forming the first lens block C1. In the third embodiment, there isarranged aperture stop ST on the image-side surface of the first lenssubstrate L12 forming the first lens block C1. In the ninth embodiment,there is arranged aperture stop ST at the closest position to the objectin image pickup lens LN. In the tenth embodiment, there is arrangedaperture stop ST between the first lens block C1 and the second lensblock C2. In each embodiment, the position of the stop is set at thecloser position to the object side than the second lens block C2, whichenhances the telecentricity as described above. Further, openingaperture ST on a surface of first lens substrate L12 is effective foreliminating unwanted light.

EXAMPLES

Hereinafter; structures of image pickup lenses in which the presentinvention is carried out, will be described specifically withconstruction data of examples. Examples 1 to 10 which will be providedlater are numerical examples corresponding to the above-described firstto tenth embodiments, respectively. The optical construction diagrams(FIGS. 1 to 10) representing the first to the tenth embodiments showlens constructions of Example 1 to 10, respectively.

In the construction data of each example, there are shown as SURFACEDATA, in order from the column at the left hand side, the surfacenumber, curvature radius “r” (mm), surface distance along the axis “d”(mm), refractive index for d-line “nd”, and Abbe number for d-line “νd”.The surface represented by the surface number followed by an asterisk“*” is an aspheric surface, and its surface shape is defined by thefollowing expression (AS) using a local Cartesian coordinate systemwhose origin is located at the surface vertex. There are further shownaspheric surface coefficients as ASPHERIC SURFACE DATA. In ASPHERICSURFACE DATA of each example, a coefficient that is not written has thevalue of zero, and “±n” means “×10^(±n) ^(u) ” for all the data

Z=(c·h ²)/[1+√{1−(1+K)·c ² ·h ²}]+Σ(Aj+h ^(j)))  (AS)

In the expression, his a height (h²=x²+y²) in the perpendiculardirection to the z-axis (optical axis AX), z is a sag amount alongoptical axis AX at the height h (measured from the surface vertex), c isa curvature radius at the surface vertex (the inverse of curvatureradius r), K is a conic constant, and Aj is a j-th order asphericcoefficient.

As VARIOUS DATA, there are shown focal length (f, mm), F-number (Fno.),half angle of view (ω, °), image height (y′max, mm), total lens length(TL, m), and back focal length (BF, m). Each of the F-number, half angleof view and back focal length is represented as an effective value forthe total lens length and the object distance (∞). The back focal lengthrepresents the distance from the rearmost lens surface to the paraxialimage plane in terms of the air-equivalent length. The total lens lengthis obtained by adding the back focal length to the distance from theforefront lens surface to the rearmost lens surface.

As LENS BLOCK DATA, there are shown focal lengths of respective lensblocks. Further, Table 1 shows values of the examples, corresponding tothe respective conditional expressions. In Table 1, the valuescorresponding to the conditional expression (1) are represented withVi1, Vi2, and Vi3 which are Abbe numbers of ia-th lens portion Li1, i-thlens substrate Li2, and ib-th lens portion Li3 of the i-th lens blockCi, respectively, and the values corresponding to the conditionalexpression (2) are represented with ri1 and ri2 which are the values forthe object-side surface and the image-side surface of the i-th lensblock Ci.

FIGS. 11 to 20 are aberration diagrams of Example 1 to 10. In FIGS. 11to 20, there are provided a spherical aberration diagram (LONGITUDINALSPHERICAL ABER), an astigmatism diagram (ASTIGMATIC FIELD CURVATURES),and a distortion diagram (DISTORTION), in order from the left hand side.The spherical aberration diagrams show a spherical aberration amount ford-line (wavelength: 587.56 nm) represented by a solid line, a sphericalaberration amount for C-line (wavelength: 656.28 nm) represented by ashorter dashed line, and a spherical aberration amount for g-line(wavelength: 435.84 nm) represented by a longer dashed line, in terms ofa displacement amount from the paraxial image plane in the direction ofoptical axis AX (unit mm, scale of the horizontal axis: from −0.200 mmto 0.200 mm), and the vertical axis represents a value obtained bynormalizing an incident height to the pupil by its maximum height (inother words, a relative height to the pupil). In the astigmatismdiagram, dashed line T or Y represents the tangential image plane ford-line and sold line S or X represents the sagittal image plane ford-line, in terms of a displacement amount from the paraxial image planein the direction of optical axis AX (unit: mm, scale of the horizontalaxis: from −0.20 mm to 0.20 mm), and the vertical axis represents theimage height (IMG HT, unit: mm). In the distortion diagrams, thehorizontal axis represents a distortion for d-line (unit: %, scale ofthe horizontal axis: from −5.0% to 5.0%), and the vertical axisrepresents the image height (IMG HT, unit: mm). Image height IMG HT isequivalent to the maximum image height y′max on the image-formingsurface (the half of the diagonal length of light-receiving surface SSof image pickup element SR).

Image pickup lens LN of Example 1 (FIG. 1) is composed of, in order fromthe object side, first lens block C1 composed of 1a-th lens portion L11which is convex toward the object side, aperture stop ST, first lenssubstrate L12, the 1b-th lens portion L13 which is concave toward theimage side; second lens block C2 composed of 2a-th lens portion L21which is concave toward the object side, second lens substrate L22, and2b-th lens portion L23 which is convex toward the image side; third lensblock C3 composed of 3a-th lens portion L31 which is convex toward theobject side, third lens substrate L32, and 3b-th lens portion L33 whichis concave toward the image side; and fourth lens block C4 composed of4a-th lens portion L41 which is convex toward the object side, fourthlens substrate L42, and 4b-th lens portion L43 which is concave towardthe image side. All the surfaces in contact with the air in the lensportions are surfaces in an aspheric shape. Each of the surfaces incontact with the air in the lens portions of the third lens block C3 andthe fourth lens block C4 includes an inflection point.

Image pickup lens LN of Example 2 (FIG. 2) is composed of, in order fromthe object side, first lens block C1 composed of 1a-th lens portion L11which is convex toward the object side, aperture stop ST, first lenssubstrate L12, and 1b-th lens portion L13 which is concave toward theimage side; second lens block C2 composed of 2a-th lens portion L21which is concave toward the object side, second lens substrate L22, and2b-th lens portion L23 which is convex toward the image side; third lensblock C3 composed of 3a-th lens portion L31 which is convex toward theobject side, third lens substrate L32, and 3b-th lens portion L33 whichis concave toward the image side; and fourth lens block C4 composed of4a-th lens portion L41 which is convex toward the object side, fourthlens substrate L42, and 4b-th lens portion L43 which is concave towardthe image side. All the surfaces in contact with the air in the lensportions are surfaces in an aspheric shape. Each of the surfaces incontact with the air in the lens portions of the third lens block C3 andthe fourth lens block C4 includes an inflection point.

Image pickup lens LN of Example 3 (FIG. 3) is composed of in order fromthe object side, first lens block C1 composed of 1a-th lens portion L11which is convex toward the object side, aperture stop ST, first lenssubstrate L12, and 1b-th lens portion L13 which is convex toward theimage side; second lens block C2 composed of 2a-th lens portion L21which is concave toward the object side, second lens substrate L22, and2b-th lens portion L23 which is convex toward the image side; third lensblock C3 composed of 3a-th lens portion L31 which is convex toward theobject side, third lens substrate L32, and 3b-th lens portion L33 whichis concave toward the image side; and fourth lens block C4 composed of4a-th lens portion L41 which is convex toward the object side, fourthlens substrate L42, and 4b-th lens portion L43 which is concave towardthe image side. A11 the surfaces in contact with the air in the lensportions are surfaces in an aspheric shape. Each of the surfaces incontact with the air in the lens portions of the third lens block C3 andthe fourth lens block C4 includes an inflection point.

Image pickup lens LN of Example 4 (FIG. 4) is composed of, in order fromthe object side, first lens block C1 composed of 1a-th lens portion L11which is convex toward the object side, aperture stop ST, first lenssubstrate L12, and 1b-th lens portion L13 which is convex toward theimage side; second lens block C2 composed of 2a-th lens portion L21which is concave toward the object side, second lens substrate L22, and2b-th lens portion L23 which is concave toward the image side; thirdlens block C3 composed of 3a-th lens portion L31 which is convex towardthe object side, third lens substrate L32, and 3b-th lens portion L33which is convex toward the image side; and fourth lens block C4 composedof 4a-th lens portion L41 which is concave toward the object side,fourth lens substrate L42, and 4b-th lens portion L43 which is concavetoward the image side. All the surfaces in contact with the air in thelens portions are surfaces in an aspheric shape. The surface in contactwith the air of the lens portion L41 at the object side in the fourthlens block C4 includes an inflection point.

Image pickup lens LN of Example 5 (FIG. 5) is composed of, in order fromthe object side, first lens block C1 composed of 1a-th lens portion L11which is convex toward the object side, aperture stop ST, first lenssubstrate L12, and 1b-th lens portion L13 which is concave toward theimage side; second lens block C2 composed of 2a-th lens portion L21which is concave toward the object side and second lens substrate 122;third lens block C3 composed of 3a-th lens portion L31 which is convextoward the object side, third lens substrate L32, and 3b-th lens portionL43 which is concave toward the image side; and fourth lens block C4composed of 4a-th lens portion L41 which is convex toward the objectside, fourth lens substrate L42, and 4b-th lens portion L43 which isconcave toward the image side. All the surfaces in contact with the airin the lens portions are surfaces in an aspheric shape. Each of thesurfaces in contact with the air in the lens portions of the third lensblock C3 and the fourth lens block C4 includes inflection point.

Image pickup lens LN of Example 6 (FIG. 6) is composed of in order fromthe object side, first lens block C1 composed of 1a-th lens portion L11which is convex toward the object side, aperture stop ST, first lenssubstrate L12, and 1b-th lens portion L13 which is concave toward theimage side; second lens block C2 composed of 2a-th lens portion L21which is concave toward the object side, second lens substrate L22, and2b-th lens portion L23 which is convex toward the image side; third lensblock C3 composed of 3a-th lens portion L31 which is convex toward theobject side, third lens substrate L32, and 3b-th lens portion L33 whichis concave toward the image side; and fourth lens block C4 composed of4a-th lens portion L41 which is convex toward the object side, fourthlens substrate L42, and 4b-th lens portion L43 which is concave towardthe image side. All the surfaces in contact with the air in the lensportions are surfaces in an aspheric shape. Each of the surfaces incontact with the air in the lens portions of the third lens block C3 andthe fourth lens block C4 includes an inflection point.

Image pickup lens LN of Example 7 (FIG. 7) is composed of in order fromthe object side, first lens block C1 composed of 1a-th lens portion L11which is convex toward the object side, aperture stop ST, first lenssubstrate L12, and 1b-th lens portion L13 which is concave toward theimage side; second lens block C2 composed of 2a-th lens portion L21which is concave toward the object side, second lens substrate L22, and2b-th lens portion 123 which is convex toward the image side; third lensblock C3 composed of 3a-th lens portion L31 which is convex toward theobject side, third lens substrate L32, and 3b-th lens portion L33 whichis concave toward the image side; and fourth lens block C4 composed of4a-th lens portion L41 which is convex toward the object side, fourthlens substrate L42, and 4b-th lens portion L43 which is concave towardthe image side. All the surfaces in contact with the air in the lensportions are surfaces in an aspheric shape. Each of the surfaces incontact with the air in the lens portions of the third lens block C3 andthe fourth lens block C4 includes an inflection point.

Image pickup lens LN of Example 8 (FIG. 8) is composed 4 in order fromthe object side, first lens block C1 composed of 1a-th lens portion L11which is convex toward the object side, aperture stop ST, first lenssubstrate L12, and 1b-th lens portion L13 which is concave toward theimage side; second lens block C2 composed of 2a-th lens portion L21which is concave toward the object side, second lens substrate L22, and2b-th lens portion L23 which is convex toward the image side; third lensblock C3 composed of 3a-th lens portion L31 which is convex toward theobject side, third lens substrate L32, and 3b-th lens portion L23 whichis concave toward the image side; and fourth lens block C4 composed of4a-th lens portion L21 which is convex toward the object side, fourthlens substrate L42, and 4b-th lens portion L43 which is concave towardthe image side. All the surfaces in contact with the air in the lensportions are surfaces in an aspheric shape. Each of the surfaces incontact with the air in the lens portions of the third lens block C3 andthe fourth lens block C4 includes an inflection point.

Image pickup lens LN of Example 9 (FIG. 9) is composed of, in order fromthe object side, aperture stop ST, first lens block C1 composed of lathlens portion L11 which is convex toward the object side, first lenssubstrate L12, and 1b-th lens portion L13 which is concave toward theimage side; second lens block C2 composed of 2a-th lens portion L21which is concave toward the object side, second lens substrate L22, and2b-th lens portion 123 which is convex toward the image side; third lensblock C3 composed of 3a-th lens portion L31 which is convex toward theobject side, third lens substrate L32, and 3b-th lens portion L33 whichis concave toward the image side; and fourth lens block C4 composed of4a-th lens portion L41 which is convex toward the object side, fourthlens substrate L42, and 4b-th lens portion L43 which is concave towardthe image side. All the surfaces in contact with the air in the lensportions are surfaces in an aspheric shape. Each of the surface incontact with the air in the lens portion at the image side in the firstlens block C1 and the surfaces in contact with the air in the lensportions of the third lens block C3 and the fourth lens block C4includes an inflection point.

Image pickup lens LN of Example 10 (FIG. 10) is composed of in orderfrom the object side, first lens block C1 composed of 1a-th lens portionL11 which is convex toward the object side, first lens substrate L12,and 1b-th lens portion L13 which is convex toward the image side;aperture stop ST; second lens block C2 composed of 2a-th lens portion121 which is concave toward the object side, second lens substrate L22,and 2b-th lens portion L23 which is convex toward the image side; thirdlens block C3 composed of 3a-th lens portion L31 which is convex towardthe object side, third lens substrate L32, and 3b-th lens portion L33which is concave toward the image side; and fourth lens block C4composed of 4a-th lens portion L41 which is convex toward the objectside, fourth lens substrate L42, and 4b-th lens portion L43 which isconcave toward the image side. All the surfaces in contact with the airin the lens portions have surfaces in an aspheric shape. Each of thesurface in contact with the air in the lens portion at the image side inthe first lens block C1 and the surfaces in contact with the air in thelens portions of the third lens block C3 and the fourth lens block C4includes an inflection point.

Construction data of Examples 1 to 10 are shown together in thefollowings.

Example 1 Unit: mm Surface Data

Surface number rd nd νdObject plane ∞∞1*1.789 0.300 1.52000 57.00

2(Stop)∞0.300 1.47400 56.40

3∞0.050 1.55000 32.004*18.611 0.8125*−2.890 0.050 1.55000 32.006∞0.300 1.47400 56.407∞0.258 152000 57.008*14.908 0.1019*1.586 0.298 1.52000 57.0010∞0.484 1.47400 56.4011∞0.148 1.52000 57.0012*3.508 022113*1.899 0.143 1.52000 57.0014∞0.484 1.47400 56.4015∞0.050 1.52000 57.0016*1.305 0.40017∞0.300 1.51600 64.1018∞0.069

Image Plane ∞ Aspheric Surface Data First Surface

K=−4.75326e−001A4=1.20011e−002A6=−1.29249e−002A8=2.25485e−002A10=−1.31516e−002A12=0.000006e+000

Fourth Surface

K=1.86879e+001A4=7.39764e−004A6=−3.18254e−003A8=−2.87821e−003A10=−139821e−003A12=0.00000e+000

Fifth Surface

K=2.77578e+000A4=−2.94996e−002A6=1.56654e−002A8=−2.26424e−002A10=1.68279e−002A12=0.00000e+000

Eighth Surface

K=1.25613e+001A4=−3.46061e−001A6=2.46884e−001A8=−9.79167e−002A18.01517e−003A12=8.12622e−003

Ninth Surface

K=−6.12637e+000A4=−1.14884e−001A6=4.52160e−002A8=−2.50140e−002A10=4.61900e−003A12=−9.12034e−004

Twelfth Surface

K=−120730e+000A4=−7.58501e−003A6=−2.93498e−002A8=7.55955e−003A10=6.97942e−004A12=−4.02481e−004

Thirteenth Surface

K=−1.02760e+001A4=−1.29413e−001A6=1.92570e−002A8=6.90908e−003A10=−1.30752e−003A12=−1.46251e−004

Sixteenth Surface

K=−6.22760e+000A4=−3.44429e−002A6=−1.44416e−002A8=7.64246e−003A10=−1.28320e−003A12=6.79087e−005

Various Data

f3.654

Fno. 2.060

ω31.125y′max 2.244

TL 4.667 BF 0.667 Lens Block Data Block Surface Focal Length

1 1-4 3.7762 5-8 −4.3893 9-12 4.7674 13-16 −13.355

Example 2 Unit: mm Surface Data

Surface number r d nd νdobject plane ∞∞1*1.444 0.300 1.52000 57.00

2(Stop)∞0.300 1.47400 56.40

3∞0.050 1.55000 32.004*6.260 0.6815*−2.460 0.050 1.55000 32.006∞0.300 1.47400 56.407∞0.300 1.52000 57.008*−18.452 0.1309*1.688 0.242 1.52000 57.0010 ∞0.441 1.47400 56.4011∞0.091 1.52000 57.0012*2.960 0.22813*1.660 0.150 1.52000 57.0014∞0.388 1.47400 56.4015∞0.050 1.52000 57.0016*1.189 0.39917∞0.300 1.51600 64.1018∞0.073Image plane ∞

Aspheric Surface Data First Surface

K=−1.40525e−001A4=1.61020e−002A6=4.04094e−003A8=3.05360e−002A10=−1.15867e−002A12=0.00000e+000

Fourth Surface

K=2.87110e+001A4=9.10195e−003A6=1.49515e−002A8=−3.31059e−002A10=4.95934e−002A12=0.00000e+000

Fifth Surface

K=5.02919e+000A4=−4.20090e−002A6=5.88712e−003A8=3.07636e−003A10=1.49479e−002A12=0.00000e+000

Eighth Surface

K=−1.60826e+000A4=−3.44334e−001A6=2.47103e−001A8=−9.73862e−002A10=1.09145e−002A12=1.15465e−002

Ninth Surface

K=−5.34940e+000A4=−1.29929e−001A6=4.85058e−002A8=−2.30448e−002A10=14.37529e−003A12=−2.50106e−004

Twelfth Surface K=4.189400-000

A4=−1.37373e−002A6=−3.23998e−002A8=8.71923e−003A10=8.82042e−004A12=−5.42462e−004

Thirteenth Surface

K=−9.63265e+000A4=−1.32449e−001A6=2.38032e−002A8=6.49067e−003A10=−1.64924e−003A12=−9.10903e−005

Sixteenth Surface

K=−6.35144e+000A4=−3.24675e−002A6=−2.00422e−002A8=8.91345e−003A10=1.17429e−003A12=3.48802e−005

Various Data

f3.515

Fno. 2.470

∞32.197y′max 2.244

TL 4.371 BF 0.670 Lens Block Data Block Surface Focal Length

1 1-4 3.4982 5-8 −5.1913 9-12 6.2344 13-16 −14.264

Example 3 Unit: mm Surface Data

Surface number r d nd νdObject surface ∞∞1*1.882 0269 1.52000 57.002∞0.300 1.47400 56.40

3(Stop)∞0.175 1.52000 57.00

4*−12.800 0.5695*−1.873 0.050 1.55000 32.006∞0.313 1.47400 56.407∞0.255 1.52000 57.008*−199.900 0.1119*1.560 0.310 1.52000 57.0010 ∞0.383 1.47400 56.4011∞0.103 1.52000 57.0012*1.799 0.11413*0.929 0.248 1.52000 57.0014∞0.300 1.47400 56.4015∞0.043 1.52000 57.0016*1.003 0.51617∞0.465 1.51600 64.1018∞0.073

Image Plane ∞ Aspheric Surface Data First Surface

K=−926361e−001A4=1.06054e−003A6=−2.63594e−002A8=2.09461e−002A10=−3.74790e−002A12=0.00000e+000

Fourth Surface

K=−1.65977e+001A4=−3.91174e−002A6=−5.92188e−002A8=9.13158e−003A10=−5.66821 e−003A12=0.00000e+000

Fifth Surface

K=7.63530e−001A4=−2.82677e−002A6=−3.05181e−004A8=−4.35936e−002A10=7.92393e−002A12=0.00000e+000

Eighth Surface

K=2.80301e+003A4=−3.47339e−001A6=2.58863e−001A8=−9.81298e−002A10=8.36197e−003A12=1.34104e−002

Ninth Surface

K=3.78246e+000A4=−1.29333e−001A6=5.54948e−002A8=−2.90945e−002A10=2.11440e−003A12=1.60054e−004

Twelfth Surface

K=−1.70477e+001A4=2.43639e−002A6=−336307e−002A8=3.94851e−003A10=4.60838e−004A12=−5.97090e−005

Thirteenth Surface

K=−4.54783e+000A4=−1.52680e−001A6=1.53960e−002A8=6.86323e−003A10=−8.00463e−004A12=−1.48550e−004

Sixteenth Surface

K=4.76306e+000A4=−5.05500e−002A6=2.44787e−002A8=1.10948e−002A10=−1.23611e−003A12=2.82574e−006

Various Data

f3.384

Fno. 2.060

ω33.330y′ max 2.244

TL 4.440 BF 0.895 Lens Block Data Block Surface Focal Length

1 1-4 3.2122 5-8 −3.4393 9-12 10.4724 13-16 6.402

Example 4 Unit: mm Surface Data

Surface number r d nd νdObject surface ∞∞1*1.626 0.248 1.52000 57.00

2(Stop)∞0.400 1.47400 56.40

3∞0.111 1.52000 57.004*−9.387 0.1175*26.887 0.051 1.52000 57.006∞0.400 1.47400 56.407∞0.078 1.63000 24.008*2.237 0.3649*154.758 0.051 1.52000 57.0010∞0.400 1.47400 56.4011∞0.300 1.52000 57.0012*−1.757 0.48013*−9.866 0.063 1.52000 57.0014∞0.400 1.47400 56.4015∞0.161 1.52000 57.0016*1.862 0.40017∞0.300 1.51633 64.1418∞0.096

Image Plane ∞ Aspheric Surface Data First Surface

K=−1.52692e−001A4=−8.35933e−003A6=1.87627e−002A8=−3.15654e−002A10=0.00000e+000A12=0.00000e+000

Fourth Surface

K=−2.69077e+001A4=3.83769e−002A6=−7.60393e−003A8=−1.46442e−002A10=0.00000e+000A12=0.00000e+000

Fifth Surface

K=−3.00000e+001A4=−9.46707e−002A6=−2.99656e−002A8=7.02903e−002A12=0.00000e+000

Eighth Surface

K=7.71871e−002A4=−4.30880e−002A6=1.39855e−002A8=−2.10002e−002A10=4.03360e−002A12=0.00000e+000

Ninth Surface

K=3.00000e+001A4=4.40707e−005A6=−1.49922e−002A8=1.51644e−002A10=−2.29754e−002A12=0.00000e+000

Twelfth Surface

K=−8.26796e+000A4=−9.74831e−002A6=8.10669e−002A8=−1.89838e−003A10=3.74246e−003A12=−4.35185e−003

Thirteenth Surface

K=2.87169e+001A4=−1.34291e−001A6=4.33820e−002A8=2.26107e−002A10=−1.20573e−002A12=1.56751e−003

Sixteenth Surface

K=−721907e+000A4=−8.99635e−002A6=3.41522e−002A8=−1.24440e−002A10=2.57011e−003A12=−2.03166e−004

Various Data

f3.667

Fno. 2.470

ω30.863y′max 2.244

TL 4.317 BF 0.694 Lens Block Data Block Surface Focal Length

1 1-4 2.7312 5-8 −3.8423 9-12 3.3464 13-16 −2.958

Example 5 Unit: mm Surface Data

Surface number r d nd νdObject plane ∞∞1*1.412 0300 1.52000 57.00

2(Stop)∞0.385 1.47400 56.40

3∞0.285 1.55000 32.004*5.607 0.5485*−2.499 0.050 1.55000 32.006∞0.300 1.47400 56.407∞0.1008*2.302 0.291 1.52000 57.009∞0.300 1.47400 56.4010 ∞0.059 1.52000 57.0011 *3.296 0.27312*1.957 0.300 1.52000 57.0013∞0.500 1.47400 56.4014∞0.081 1.52000 57.0015*1.837 0.37116∞0.369 1.51600 64.1017∞0.070Image plane ∞

Aspheric Surface Data First Surface

K=−2.27747e−001A4=5.84302e−003A6=3.02365e−002A8=−3.17392e−002A10=2.18523e−002A12=0.00000e+000

Fourth Surface

K=2.52211e+001A4=1.61699e−002A6=−5.07108e−002A8=9.41184e−002A10=−1.04400e−001A12=0.00000e+000

Fifth Surface

K=6.65378e+000A4=6.63051e−002A6=2.47045e−002A8=−1.25025e−001A10=6.98031e−002A12=0.00000e+000

Eighth Surface

K=−1.31238e+000A4=−7.39376e−002A6=2.54659e−002A8=4.49728e−002A10=8.07536e−003A12=−2.97025e−003

Eleventh Surface

K=−3.40141e+001A4=−3.10958e−002A6=−6.00860e−003A8=4.67715e−003A10=1.07136e−004A12=−3.51326e−004

Twelfth Surface K=−3.749920-000

A4=−1.44565e−001A6=1.90908e−002A8=7.39784e−003A10=−1.48746e−003A12=−1.02123e−006

Fifteenth Surface

K=−5.67542e+000A4=−2.84325e−002A6=1.28707e−002A8=6.20385e−003A10=−1.15838e−003A12=8.09209e−005

Various Data

f3.792

Fno. 2.470

ω30.203y′max 2.244

TL 4.456 BF 0.684 Lens Block Data Block Surface Focal Length

1 1-4 3.4102 5-7 −4.5433 8-11 11.9594 12-15 36.993

Example 6 Unit: mm Surface Data

Surface number r d nd νdObject plane ∞∞1*1.628 0.283 1.59325 61.81

2(Stop) ∞0.422 1.75520 27.58

3∞0.100 1.60083 38.554*8.838 0.6365*−2.722 0.050 1.75520 27.586∞0.300 1.53888 65.537∞0.300 1.64608 55.728*−16.892 0.1209*1.750 0.181 1.57706 41.91 ∞0.340 1.51173 58.3111∞0.161 1.49528 69.5512*3.151 026613*1.904 0.131 1.66173 43.5514∞0.361 1.60775 37.7115∞0.100 1.72532 33.6016*1.402 0.34917∞0.300 1.51600 64.1018∞0.100

Image Plane ∞ Aspheric Surface Data First Surface

K=−4.67355e−001A4=1.15537e−002A6=−8.69132e−003A8=1.96242e−002A10=−2.28004e−002A12=0.00000e+000

Fourth Surface

K=5.53072e+000A4=−1.58919e−002A6=−2.72905e−002A8=8.62561e−003A10=−3.54272e−002A12=0.00000e+000

Fifth Surface

K=5.94882e+000A4=−5.55947e−002A6=−6.31900e−003A8=−1.64814e−002A10=3.72827e−002A12=0.00000e+000

Eighth Surface

K=−3.00000e+001A4=−3.36016e−001A6=2.40691e−001A8=−1.01117e−001A10=1.16935e−002A12=1.50988e−002

Ninth Surface

K=−6.51594e+000A4=−1.33093e−001A6=436202e−002A8=−2.21686e−002A10=5.85236e−003A12=−3.95211e−004

Twelfth Surface

K=−1.77791e+000A4=−1.24462e−002A6=−3.51321e−002A8=8.76536e−003A10=1.33383e−003A12=−5.46510e−004

Thirteenth Surface

K=−1.20454e+001A4=−1.24010e−001A6=2.82975e−002A8=4.18931e−003A10=−1.84819e−003A12=1.14973e−004

Sixteenth Surface

K=−8.48783e÷000A4=−3.79551e−002A6=−1.25975e−002A8=7.43245e−003A10=−1.20284e−003A12=5.84609e−005

Various Data

f3.417

Fno. 2.060

ω33.079y′max 2.244

TL 4.398 BF 0.647 Lens Block Data Block Surface Focal Length

1 1-4 3.2422 5-8 −4.2583 9-12 5.1114 13-16 −9.552

Example 7 Unit: mm Surface Data

Surface number r d nd νdObject plane ∞∞1*1.550 0253 1.60997 60.87

2(Stop) ∞0.300 1.48749 70.40

3∞0.050 1.60506 38.034*8.727 0.4665*−2.673 0.050 1.73433 28.486∞0.300 1.48749 70.407∞0.225 1.74397 44.858*−9.578 0.1369*1.803 0.166 1.61279 60.7210∞0.300 1.48749 70.4011∞0.048 1.48749 70.4012*2.612 0.20513*1.526 0.167 1.74650 39.2614∞0.300 1.48749 70.4015 ∞0.069 1.73632 43.0216*1.127 0.36517∞0.300 1.51600 64.1018∞0.100Image plane ∞

Aspheric Surface Data First Surface

K=6.01845e−001A4=6.23429e−003A6=−5.17189e−003A8=2.55890e−002A10=−1.36820e−001A12=0.00000e+000

Fourth Surface

K=3.00000e+001A4=−3.80854e−002A6=−8.08638e−002A8=−6.41584e−002A10=−5.59564e−002A12=0.00000e+000

Fifth Surface

K=8.31958e+000A4=−7.75198e−002A6=2.39089e−003A8=6.15111e−003A10=−1.1.7591e−002A12=0.00000e+000

Eighth Surface

K=−3.00000e+001A4=−3.17831e−001A6=2.50137e−001A8=−9.60165e−002A10=1.85760e−002A12=2.22750e−002

Ninth Surface

K=−4.40151e+000A4=−1.45101e−001A6=4.78489e−002A8=−2.04806e−002A10=6.05309e−003A12=−4.20998e−004

Twelfth Surface

K=−231084e+000A4=−1.66094e−002A6=−3.80712e−002A8=8.94230e−003A10=−1.59274e−003A12=5.55958e−004

Thirteenth Surface

K=−9.90648e+000A4=−1.17442e−001A6=2.72393e−002A8=3.70320e−003A10=−1.79962e−003A12=1.52153e−004

Sixteenth Surface

K=−7.47538e+000A4=−4.99613e−002A6=−1.19908e−002A8=7.61547e−003A10=−1.17917e−003A12=5.80836e−005

Various Data

f2.781

Fno. 2.880

ω38.941y′max 2.244

TL 3.698 BF 0.663 Lens Block Data Block Surface Focal Length

1 1-4 2.9882 5-8 −5.2813 9-12 5.7244 13-16 −17.749

Example 8 Unit: mm Surface Data

Surface number r d nd νdObject plane ∞∞1*1.426 0.300 1.52000 57.00

2(Stop) ∞0.300 1.47400 56.40

3∞0.050 1.55000 32.004*7.210 0.6885*−2.345 0.054 1.55000 32.006∞0.300 1.47400 56.407∞0.300 1.52000 57.008*−5.716 0.1009*2.353 0.246 1.52000 57.0010∞0.438 1.47400 56.4011∞0.106 1.52000 57.0012*2.049 0.14513*1.496 0.201 1.52000 57.0014∞0.422 1.47400 56.4015∞0.063 1.52000 57.0016*1.410 0.35717∞0.300 1.51600 64.1018∞0.102

Image Plane ∞ Aspheric Surface Data First Surface

K=−1.80349e−001A4=1.31336e−002A6=5.09787e−003A8=2.05659e−002A10=1.13963e−002A12=0.00000e+000

Fourth Surface

K=2.34387e+001A4=5.72689e−003A6=1.51484e−002A8=−3.06918e−002A10=1.70585e−002A12=0.00000e+000

Fifth Surface

K=5.10401e+000A4=−2.93333e−002A6=1.48837e−002A8=−1.90924e−003A10=2.78023e−002A12=0.00000e+000

Eighth Surface

K=−3.00000e+001A4=−3.16114e−001A6=2.45397e−001A8=−9.59528e−00210=1.39708e−002A12=1.08602e−002

Ninth Surface

K=−1.15065e+001A4=−1.50388e−001A6=5.55256e−002A8=−2.06017e−002A10=3.53249e−003A12=−9.75558e−004

Twelfth Surface

K=−7.78236e+000A4=−1.19675e−002A6=−232920e−002A8=7.84045e−003A10=6.12696e−004A12=−5.82408e−004

Thirteenth Surface

K=−627127e+000A4=−1.16359e−001A6=2.17572e−002A8=6.13835e−003A10=−1.74318e−003A12=−8.85684e−005

Sixteenth Surface

K=−5.59825e+000A4=−3.72373e−002A6=−1.72973e−002A8=8.49298e−003A10=1.19232e−003 A12=3.96396e−005

Various Data

f3.565

Fno. 2.470

ω31.833y′ max 2.244

TL 4.370 BF 0.656 Lens Block Data Block Surface Focal Length

1 1-4 3.3292 5-8 −7.4473 9-12 −328.4094 13-16 26.409

Example 9 Unit: mm Surface Data

Surface number r d nd νdObject plane ∞∞

1(Stop) ∞0.053

2*1.789 0.297 1.52000 57.003∞0.305 1.47400 56.404∞0.058 1.55000 32.005*26.025 0.5696*−2.478 0.050 1.55000 32.007∞0.319 1.47400 56.408∞0.300 1.52000 57.009*552.419 0.14210*1.497 0.312 1.52000 57.0011∞0.395 1.47400 56.4012∞0.050 1.52000 57.0013*2.591 0.26014*1.178 0.202 1.52000 57.0015∞0.309 1.47400 56.4016∞0.046 1.52000 57.0017*1.003 0.53818∞0.431 1.51600 64.1019∞0.060

Image Plane ∞ Aspheric Surface Data Second Surface

K=−5.65901e−001A4=1.09110e−002A6=−1.66285e−002A8=3.26829e−002A10=−2.71803e−002A12=0.00000e+000

Fifth Surface

K=1.12444e+001A4=5.74187e−003A6=−3.01066e−002A8=1.65044e−002A10=−1.66572e−002A12=0.00000e+000

Sixth Surface K=8.866620-001

A4=−5.15421e−002A6=9.74565e−003A8=−4.23313e−002A10=4.49480e−002A12=0.00000e+000

Ninth Surface

K=4.38368e+004A4=−3.57324e−001A6=253040e−001A8=−1.00918e−001A10=7.93632e−003A12=1.27856e−002

Tenth Surface

K=−3.78234e+000A4=−1.20964e−001A6=5.61392e−002A8=−3.00977e−002A10=2.42559e−003A12=9.44484e−004

Thirteenth Surface

K=−1.42305e+001A4=3.04354e−002A6=−3.62786e−002A8=4.74497e−003A10=7.17403e−004A12=−4.34524e−005

Fourteenth Surface

K=−4.88422e+000A4=−1.68189e−001A6=1.65102e−002A8=7.80191e−003A10=−6.67224e−00412=−1.50476e−004

Seventeenth Surface

K=4.76306e+000A4=−5.05500e−002A6=−2.44787e−002A8=1.10948e−002A10=−1.23611e−003A12=2.82574e−006

Various Data

f3.418

Fno. 2.470

ω32.966y′max 2.244

TL 4.547 BF 0.882 Lens Block Data Block Surface Focal Length

1 2-5 16732 6-9 −4.4853 10-13 5.4954 14-17 119.498

Example 10 Unit: mm Surface Data

Surface number r d nd νdObject plane ∞∞1*1.944 0.300 1.52000 57.002∞0.300 1.47400 56.403∞0.064 1.55000 32.004*−118.952 0.100

5(Stop)∞0.545

6*−2.212 0.073 1.55000 32.007∞0.321 1.47400 56.408∞0300 1.52000 57.009*−175.781 0.16610*1.404 0.312 1.52000 57.0011∞0.405 1.47400 56.4012∞0.063 1.52000 57.0013*2.528 0.23314*1.170 0.198 1.52000 57.0015∞0.308 1.47400 56.4016∞0.035 1.52000 57.0017*1.003 0.54118∞0.436 1.51600 64.1019∞0.072

Image Plane ∞ Aspheric Surface Data First Surface

K=−7.15407e−001A4=7.54788e−003A6=−2.05108e−002A8=2.93135e−002A10=−2.96175e−002A12=0.00000e+000

Fourth Surface

K=−2.67412e+000A4=−1.26958e−002A6=−3.42547e−002A8=1.34369e−002A10=−2.10165e−002A12=0.00000e+000

Sixth Surface

K=1.06166e+000A4=−5.50222e−002A6=6.93157e−003A8=−4.09519e−002A10=5.58288e−002A12=0.00000e+000

Ninth Surface

K=4.31616e+001A4=−3.59685e−001A6=2.51226e−001A8=−1.02607e−001A10=6.24533e−003A12=1.15289e−002

Tenth Surface

K=−3.31796e+000A4=1.16673e−001A6=5.67553e−002A8=−2.98548e−002A10=2.61045e−003A12=1.09996e−003

Thirteenth Surface

K=−1.30241e+001A4=2.61905e−002A6=−3.68914e−002A8=4.78505e−003A10=−7.60679e−004A12=−3.10586e−005

Fourteenth Surface

K=−4.70506e+000A4=4.66876e−001A6=1.65823e−002A8=7.74821e−003A10=−7.03131e−004A12=−1.58993e−004

Seventeenth Surface

K=−4.76306e+000A4=−5.05500e−002A6=−2.44787e−002A8=1.10948e−002A10=−1.23611e−003A12=2.82574e−006

Various Data

f3.456

Fno. 2.470

ω32.786y′ max 2.244

TL 4.623 BF 0.900 Lens Block Data Block Surface Focal Length

1 1-4 3.6822 6-9 −4.0763 10-13 4.8914 14-17 105.894

TABLE 1 Example 1 Example 2 Example 3 Example 4 Example 5 (1) νn V13:32.0 V13: 32.0 V21: 32.0 V23: 24.0 V13: 32.0 V21: 32.0 V21: 32.0 — —V21: 32.0 (2) |m/f| r12: 5.09 r12: 1.78 r21: 0.55 r22: 0.61 r12: 1.48r21: 0.79 r21: 0.70 — — r21: 0.66 (3) f1/f 1.03 1.00 0.95 0.74 0.90 (4)f2/f −1.20 −1.48 −1.02 −1.05 −1.20 (5) |f3/f| 1.30 1.77 3.09 0.91 3.15(6) (D1a + D2a + D3a)/f 0.31 0.30 0.23 0.26 0.24 Example 6 Example 7Example 8 Example 9 Example 10 (1) νn V13: 38.6 V13: 38.0 V13: 32.0 V13:32.0 V21: 32.0 V21: 27.6 V21: 28.5 V21: 32.0 V21: 32.0 — V43: 33.6 — — —— (2) |m/f| r12: 2.59 r12: 3.14 r12: 2.02 r12: 7.61 r21: 0.64 r21: 0.80r21: 0.96 r21: 0.66 r21: 0.72 — r42: 0.41 — — — — (3) f1/f 0.95 1.070.93 1.07 1.07 (4) f2/f −1.25 −1.90 −2.09 −1.31 −1.18 (5) |f3/f| 1.502.06 92.12 1.61 1.42 (6) (D1a + D2a + D3a)/f 0.30 0.29 0.26 0.28 0.30

REFERENCE SIGNS LIST

-   -   CU Mobile terminal    -   LU Image pickup apparatus    -   LN Image pickup lens    -   Ci i-th lens block    -   Li1 ia-th lens portion    -   Li2 i-th lens substrate    -   Li3 ib-th lens portion    -   ST Aperture stop (stop)    -   SR Image pickup element    -   SS light-receiving surface    -   IM Image plane (optical image)    -   AX Optical axis    -   B1 Spacer member    -   1 Signal processing section    -   2 Control section    -   3 Memory    -   4 Operation section    -   5 Display section

1. An image pickup lens comprising four or more lens blocks, whereineach of the lens blocks is an optical element comprising a lenssubstrate being a parallel flat plate, and a lens portion or lensportions having positive or negative power and formed on at least one ofan object-side surface and image-side surface of the lens substrate, thelens substrate is different in material from the lens portion or lensportions in each of the lens blocks, the lens blocks include, in orderfrom an object side, a first lens block, a second lens block, a thirdlens block, and a fourth lens block, the first lens block has positivepower, the second lens block has negative power, a lens block arrangedat a closest position to an image side has a concave shape facing theimage side in a paraxial region, at least one of lens portions eachhaving a concave shape in the paraxial region satisfies the followingconditional expression (1), and the first lens block satisfies theconditional expression (3):νn<40  (1)0.5<f1/f<1.5  (3) where νn is an Abbe number of a lens portion having aconcave shape in the paraxial region, f1 is a composite focal length ofthe first lens block, and f is a composite focal length of a totalsystem of the image pickup lens.
 2. The image pickup lens of claim 1,wherein the at least one of lens portions satisfying the conditionalexpression (1) satisfies the conditional expression (2):0.5<|m/f|<1.0  (2) where m is a curvature radius of the surface having aconcave shape in the paraxial region.
 3. The image pickup lens of claim1, comprising a stop arranged at a closer position to the object sidethan the second lens block.
 4. The image pickup lens of claim 1,satisfying the following conditional expression (3a):0.7<f1/f<1.2  (3a) where f1 is a composite focal length of the firstlens block.
 5. The image pickup lens of claim 1, satisfying thefollowing conditional expression (4):−2.5<f2/f<−0.9  (4) where f2 is a composite focal length of the secondlens block.
 6. The image pickup lens of claim 1, wherein the second lensblock has a convex shape facing the image side in the paraxial region.7. The image pickup lens of claim 1, satisfying the followingconditional expression (5):0.8<|f3/f1<3.0  (5) where f3 is a composite focal length of the thirdlens block.
 8. The image pickup lens of claim 1, wherein the third lensblock has a concave shape facing the image side in the paraxial region.9. The image pickup lens of claim 1, wherein a rearmost lens surface ofthe image pickup lens includes an inflection point.
 10. The image pickuplens of claim 1, being a four-block structure.
 11. The image pickup lensof claim 10, wherein the fourth lens block has negative power.
 12. Theimage pickup lens of claim 1, satisfying the following conditionalexpression (6):(D1a+D2a+D3a)/f<0.35  (6) where D1a is a distance along an optical axisbetween the first lens block and the second lens block, D2a is adistance along the optical axis between the second lens block and thethird lens block, and D3a is a distance along the optical axis betweenthe third lens block and the fourth lens block.
 13. The image pickuplens of claim 1, wherein all of the lens substrates are parallel flatplates having a same thickness.
 14. The image pickup lens of claim 1,wherein each of the lens substrates is formed of a glass material. 15.The image pickup lens of claim 1, wherein each of the lens portions isformed of a resin material.
 16. The image pickup lens of claim 15,wherein the resin material is an energy-curable resin material.
 17. Theimage pickup lens of claim 15, wherein inorganic particles with a sizeof 30 nanometers or less are dispersed in the resin material.
 18. Theimage pickup lens of claim 1, wherein the lens blocks are manufacturedby a manufacturing process comprising: a step of sealing an area betweenthe lens substrates with a spacer member formed in a grid shape; and astep of cutting the lens substrates and the spacer member which havebeen joined together, along a framework of a grid of the spacer member.19. An image pickup apparatus characterized by comprising: the imagepickup lens of claim 1; and an image pickup element for converting anoptical image formed on an light-receiving surface into electric signal,wherein the image pickup lens is arranged so as to form an optical imageof a subject on the light-receiving surface of the image pickup element.20. A mobile terminal comprising the image pickup apparatus of claim 19.